In order to support higher data rate and spectrum efficiency, the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) system has been introduced into 3GPP Release 8 (R8). (LTE Release 8 may be referred to herein as LTE R8 or R8-LTE.) In LTE, transmissions on the uplink are performed using Single Carrier Frequency Division Multiple Access (SC-FDMA). In particular, the SC-FDMA used in the LTE uplink is based on Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) technology. As used hereafter, the terms SC-FDMA and DFT-S-OFDM are used interchangeably.
In LTE, a wireless transmit/receive unit (WTRU), alternatively referred to as a user equipment (UE), transmits on the uplink using only a limited, contiguous set of assigned sub-carriers in a Frequency Division Multiple Access (FDMA) arrangement. For example, if the overall Orthogonal Frequency Division Multiplexing (OFDM) signal or system bandwidth in the uplink is composed of useful sub-carriers numbered 1 to 100, a first given WTRU may be assigned to transmit on sub-carriers 1-12, a second WTRU may be assigned to transmit on sub-carriers 13-24, and so on. While the different WTRUs may each transmit into only a subset of the available transmission bandwidth, an evolved Node-B (eNodeB) serving the WTRUs may receive the composite uplink signal across the entire transmission bandwidth.
LTE Advanced (which includes LTE Release 10 (R10) and may include future releases such as Release 11, also referred to herein as LTE-A, LTE R10, or R10-LTE) is an enhancement of the LTE standard that provides a fully-compliant 4G upgrade path for LTE and 3G networks. In LTE-A, carrier aggregation is supported, and, unlike in LTE, multiple component carriers (CCs) may be assigned to the uplink, downlink, or both. Such carriers may be asymmetric (a different number of CCs may be assigned to the uplink than the number of CCs assigned to the downlink.) Note that CCs may also be known as cells, and in this disclosure the terms are used interchangeably.
In both LTE and LTE-A, there is a need to transmit certain associated layer 1/layer 2 (L1/2) uplink control information (UCI) to support the uplink (UL) transmission, downlink (DL) transmission, scheduling, multiple-input multiple-output (MIMO), etc. In LTE, if a WTRU has not been assigned an uplink resource for UL transmission of data (e.g., user data), such as a Physical UL Shared Channel (PUSCH), then the L1/2 UCI may be transmitted in a UL resource specially assigned for UL L1/2 control on a physical uplink control channel (PUCCH). What are needed in the art are systems and methods for transmitting UCI and other control signaling utilizing the capabilities available in an LTE-A system, including carrier aggregation.